Catheter Oxygen Sensor for Real-Time AKI Risk Assessment
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Solution Overview
Problem
Current methods for diagnosing acute kidney injury (AKI) during cardiac surgery are inadequate due to the lack of real-time monitoring of renal perfusion, relying on delayed serum creatinine levels and urine output, which are insensitive to acute changes and invasive renal vein cannulation.
Innovation Solution
A catheter assembly with an integrated oxygen-sensing assembly that includes a urinary catheter, an oxygen sensor, a flowrate sensor, and a control system to detect oxygen levels, flowrate, and temperature, enabling real-time measurement of oxygen tension and mass flowrate of oxygen in urine, thereby assessing the risk of AKI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If serum creatinine levels and urine output are used to diagnose AKI, then diagnosis can be made using conventional methods, but there is a significant time lag of 24 to 36 hours between actual injury and diagnosis
Solution Approach 1:
The patent measures urinary oxygen tension as an early biomarker before traditional markers like serum creatinine rise. By performing this measurement preliminarily and continuously, the system detects renal injury at its earliest stages, enabling intervention before permanent damage occurs and eliminating the 24-36 hour delay inherent in conventional creatinine-based diagnosis
Solution Approach 2:
The patent introduces urinary oxygen tension as an intermediary biomarker that provides real-time information about renal perfusion and injury. This intermediary measurement occurs between the actual injury event and the delayed rise in serum creatinine, filling the diagnostic gap with continuous, real-time data that reflects acute changes in renal function
2Reliability
If invasive renal vein cannulation is performed to measure renal blood flow, then real-time monitoring of renal perfusion is achieved, but the procedure is highly invasive and not utilized routinely
Solution Approach 1:
The patent uses urinary oxygen tension as a non-invasive intermediary indicator that reflects renal perfusion status without requiring direct invasion of the renal vein. Urine serves as a surrogate medium that carries information about renal oxygenation and perfusion, allowing clinicians to monitor renal health through a routine urinary catheter rather than performing hazardous cannulation procedures
Solution Approach 2:
The patent replaces the mechanical invasive procedure of renal vein cannulation with a chemical/biochemical sensing approach. Instead of physically accessing the renal vein to measure blood flow, the system uses an oxygen sensor to detect oxygen tension in urine, substituting a minimally invasive chemical measurement for a highly invasive mechanical procedure
3Ease of operation
If urinary flowrate is used as an indicator of renal perfusion, then measurement is non-invasive and easy to obtain, but urine output is affected by volume status, anesthetic drugs, and diuretics making it insensitive to acute changes in renal function
Solution Approach 1:
The patent segments the measurement process into two independent components: urinary flowrate measurement and urinary oxygen tension measurement. While flowrate provides information about urine production, the oxygen tension measurement provides separate, complementary information about renal perfusion and oxygen delivery. This segmentation allows the system to overcome the limitations of flowrate alone by combining it with oxygen tension data that is not affected by volume status or diuretic use
Solution Approach 2:
The patent introduces urinary oxygen tension as an additional intermediary parameter that complements urinary flowrate. While flowrate is influenced by multiple factors including diuretics and volume status, oxygen tension provides a more direct and accurate reflection of renal perfusion and oxygen delivery, acting as a more reliable intermediary marker for assessing acute changes in renal function
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Provides continuous and real-time monitoring of kidney hypoxia, reducing the risk of AKI by detecting urinary hypoxia before permanent injury occurs, facilitating early intervention and improving patient outcomes.
Implementation Method 1
an oxygen sensor in operable communication with the flow pathway of the housing, the oxygen sensor configured to detect oxygen tension of a fluid flowing through the flow pathway
Implementation Method 2
a flowrate sensor disposed between the oxygen sensor and the inlet end of the housing and configured to detect a flowrate of the fluid flowing through the flow pathway
Implementation Method 3
a temperature sensor disposed downstream of the oxygen sensor and configured to detect a temperature of the fluid flowing through the flow pathway
Data Source
AI summary
An oxygen-sensing assembly for attachment to a urinary catheter may include a housing having a flow pathway extending between an inlet end and an outlet end thereof, an oxygen sensor in operable communication with the flow pathway of the housing, the oxygen sensor configured to detect oxygen levels of a fluid flowing through the flow pathway and a flowrate sensor configured to detect a flowrate of the fluid flowing through the flow pathway. A risk of acute kidney injury may be determined based on the mass flowrate of oxygen through the flow pathway, determined based on the detected oxygen levels and the flowrate of the fluid through the flow pathway. Related catheter assemblies and methods are also disclosed.